Hi Alan - I didn’t say cooling is faster than heating, I said I think its possible that the fact that styrofoam takes longer to heat up and longer to cool down could be somehow contributing to a lower performance. Its conjecture and not backed up by any scientific reasoning (maybe it has something to do with the relationship between the air, the glass and the cooler mass/higher specific heat capacity of the wine itself) but the conventional wisdom amongst fulfillment providers to the wine business (that I have spoken with at least, over the years) is that pulp shippers are a better medium for shipping wine through common carriers such as UPS and FedEx. I am going to ask my FedEx rep if they have anything pertinent here…also, see the article I posted above with WBM monthly link. In my mind, its not clear-cut that styrofoam is better medium for shipping. I’ll report back what I find out from FedEx if anything.
Next round - cardboard shipper, full case.
And the results:
It certainly looks like having the 12 bottles creates a larger thermal mass that moderates the temp variation.
Next up, styro with the same parameters.
oh wow. i’m surprised how well a full case in a cardboard shipper moderates temp. Even with two days of highs of 90+ it barely gets past 75
I’ll be very curious to see how the Styrofoam affects the amount of time it takes for the wine to rise up from cellar temperature. I think that’s probably the main reason why people are still using those shippers. This may or may not be a Mythbusters situation.
Paul, really interesting and useful! Would also be interesting to see the results with the probe in an outer bottle. I’m actually amazed, as Chalie says, how good the cardboard seems to be, that’s a bit of a surprise. Although maybe not as much as we might think - I keep a couple of cases of everyday drinkers at home, just sitting on the tile floor in my house. That floor stays quite a bit cooler than the air temp, so at the end of a warm day when my house temp might get as high as 85, you can open one of those cases and feel a distinct coolness right away. I assume it’s mostly the mass of the wine, but even a little cardboard insulation is worth something.
I, too, was surprised at how well the cardboard shipper performed. I’m in the middle of the styro run now - it looks to be performing better. I’ll post the results in a couple of days.
Cameron - that study regarding the pulp shippers was discussed on this board a couple times, most recently a few months ago. Most people dismissed it. I like what Paul just showed with his cardboard shipper though. That’s even more interesting because that box is not built to insulate at all, just to protect the wine.
Great work Paul.
Thanks for the new data. The 12 bottle curve even in just cardboard looks like I would expect. I am going to guess that the styro curve will have the same basic shape with an initial rapid rise in temp but to a slightly lower point and the a more gradual increase up to account for the better insulating properties of the styro.
The downside of your doing this is that now all my future orders will be in case quantities.
Greg, something to remember is that heat transfer is always a lot slower without convection (thus the value of ceiling fans). Just having a barrier to air flow around the bottles is worth a lot, and cardboard is actually not a bad insulator (tables of R-values show cardboard at 3-4, polystyrene at around 4, so not that much different except that styro is usually thicker). That particular cardboard box has a double layer on the outside, so should be better than just a normal wine box. Still, I’m a bit surprised how well it did, and will be interested in seeing the result for the styro shipper.
Yes, interesting stuff. Alan makes good point the cardboard shipper used by Paul is a bit more well-built than most “pulp” shippers.
First of all, thanks to Paul to taking the time to do these experiments. For my own purposes, I bought a bunch of temp monitoring equipment a couple weeks ago as I want to see the real world effects of actually shipping in the middle of summer…hopefully soon I can get around to actually doing it.
First experiment: Two packages, one 12x styro and one 12x “pulp” shipper (same we use every day for our dtc shipments), will be shipped at the same time first to Texas via FedEx ground (once I get them back I’ll do Florida and DC FedEx ground). Two bottles in each box will have a temp tracker (the metal plugs in pic below fit in the bottle) to get liquid temps for top and bottom of box bottle placement and each box will have a temp tracker (LogTag) at the top of the box to measure ambient air temps. Hopefully I can get it done this week, just need to go buy a styro box. Keep you posted.
I was going to make the same point as Alan did, namely that one of the main things the cardboard is doing is preventing convection (prevents circulation of hot air to replace air initially cooled by the cooler bottles). But, those traces show that the insulating value of the cardboard is not very high. Basically, when something is insulated there is a time lag between the outside air temperature rising above (or below) and the corresponding change starting in the insulated object (better insulated, longer lag). If you look at those curves, there is a small lag but not a very long one.
-Al
Now for the Styro results. Was very fortunate to have a temperature profile that almost matches the run from the cardboard shipper, but keep in mind the styro run did get the slightly warmer conditions (especially the low temps).
I’ve included the cardboard data (dashed lines) for comparison.
I think it’s pretty clear that the styro outperforms the cardboard (sorry Cameron!), certainly for the 3 day time period. The styro kept the wine cooler, even under warmer conditions.
Next up:
Cardboard shipper + Wine Check.
I also want to do a run with the probed bottle on an outside edge or corner position.
That’s a good simulation, but it is worth pointing out that the real-world measurements show that the daily temperature fluctuations are not strictly sinusoid. The high peaks are considerably narrower than the low troughs, and this very likely has a fairly dramatic impact on the true average temperatures.
To be honest, it looks like the cardboard isn’t performing much worse than the styrofoam.
-Al
Yeah, quite negligible - hard to tell the difference without having them in the same external climate conditions day/night
Hmmm… this data argues that you can do 2 or 3 day shipping without any problems in the summer. If you stick the bottles in the fridge overnight to cool it down even further, you might even get away with standard ground shipping.
I could modify the model, but honestly, I don’t think it would make a big difference. It will just shift the bottle trace down a little bit, to reflect the fact that there is a lower temperature for a little longer each period.
I gotta think that shipping trucks get even hotter than these temps.
On first glance, I was thinking along those lines. But then I got to thinking that the temperature on the inside of a freight car or trailer of an 18-wheeler is likely going to be a lot warmer than the ambient air temp. The interior of a Fedex truck when it’s 95 out is probably 120+, which pushes the bottle temp into the 80s at least.
Or what Charlie said, his post came in while I was dawdling over mine.
The difference is noticeable on day one where the cardboard sees lower temps (highs and lows) so the total area under the curve is significantly less but results in a higher rise in bottle temp. Based on the first few hours of data, it looks like the cardboard jumps 5 degrees while the stryo moves only 2 in the same time with basically the same ramp up in temp so the Stryo is way better when the temp profiles start to diverge. I think the reason that it looks as close as it does is the different temp profiles from the two runs and because of the thermal mass of the full case and if repeated with a shipper that was half full the difference in results would be more obvious.